Fire safety is a concern in the construction of frame wall buildings. When such a building is intended for human occupancy, fire safety increases in importance, as the occupants may often be asleep, hence especially vulnerable, in the event of a fire. Construction techniques that inhibit the rapid spread of fire are therefore common in the construction industry.
One such frame-wall construction technique is the affixment of firestops between adjacent studs. It is the function of a firestop to "stop" (i.e., block or close up) the cavity between the studs. By so doing, the ability of the cavity to act as a chimney for smoke, combustion gasses, etc., is inhibited, and the ability of the fire to spread up the wall to an upper story or roof is inhibited.
One modern frame-wall construction technique utilizes metal channeling, typically formed of sheet steel, as studs and other framing members. Structures utilizing such metal-frame construction provide an alternative to traditional wood-frame structures, offering reduced construction time, improved strength, decreased weight, and a significant reduction in overall flammability.
Inasmuch as such metal framing members are channels having a substantially U-shaped cross section, hence an open interior space, a problem arises in the fitting of firestops. Unless interior space would provide an opening around a firestop sufficient to produce a chimney effect in the event of a fire. This poses a significant safety hazard.
Conventional metal-frame construction requires that a firestop be conformingly trimmed so as to occlude the interior space of the stud(s) to which it is affixed. This is a labor-intensive process, involving the use of snips or other hand-operated cutters. Such a process is time-consuming, hence costly. What is needed, therefore, is a way to affix a firestop between studs in a metal-frame structure that occludes the stud interior space wherein the only cutting of the firestop is to length, i.e., without requiring the firestop to be trimmed or cut to shape. This methodology often inadequately occludes the interior space of at least one of the adjacent framing members, requiring the insertion of rock wool, fiberglass, or other occludent material.
Additionally, conformingly trimming a firestop by hand poses a potential danger to the worker. The cut edges of sheet-steel channels tend to be sharp. In the course of trimming and otherwise manipulating the firestop, a significant risk of laceration or other injury is present. What is needed, therefore, is a reduction of conformingly trimming and/or handling of the firestop so as to reduce the potential for injury.
Also, because such metal framing members have U-shaped cross sections, the use of metal studs in closely studded areas, such as wall corners and junctions, creates a vertical cavity. This is in marked contrast to the use traditional wood studs which, being solid, do not produce such a cavity. Such vertical cavities act as chimneys in the event of fire. Provisions should be made in metal-frame structures to occlude such chimneys. Again, these provisions conventionally require the insertion of a short, conformingly trimmed firestop. What is needed in this case is a way of occluding the resultant vertical cavities without interfering with the spacing and distribution of such close-proximity studs.